Method of fabricating laminate-like structures



April 21, 1970 J. J. AFFEL 3,507,724

METHOD OF FABRICATING LAMINATE-LIKE STRUCTURES Filed Sept. 22, 1967 2 Sheets-Sheet- 1 lj ra. 1. 5

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METHOD OF FABRICATING LAMINATELIKE STRUCTURES A ril 21, 1970 3 Sheets-Sheet 2 90. 8.

04 7945 ON! C GENE/Q0 TOE Filed Sept.

PZESSUEE PLQTE United States Patent O 3,507,724 METHOD OF FABRICATING LAMINATE-LIKE STRUCTURES John J. Affel, Canoga Park, Calif., assignor to International Telephone and Telegraph Corporation, New

York, N.Y., a corporation of Maryland Filed Sept. 22, 1967, Ser. No. 669,760 Int. Cl. B29c 27/08 US. Cl. 156-73 9 Claims ABSTRACT OF THE DISCLOSURE A number wheel for use in a counter or other like device and embodying a novel construction of a number Wheel and operatively associated parts, including a unitary sandwich of the wheel integral with a primary wheel hub, a spring detent member, and a secondary hub, the latter rotatably mounting and confining a driver gear element, with a spring and pawl reset mechanism confined in a recess in the sandwich. Also involved is the method of fabricating such a number wheel by a series of mechanical steps including ultrasonic welding for unitina wheel hubs in forming the sandwich.

BACKGROUND OF THE INVENTION In counters and other devices of generally similar characteristics, it is customary to rotate a number wheel or the like by means of a cable, shaft, pawl escapement or other means. Thus, a mechanism turns the first wheel whereby distance or other measure is recorded in angular movement of the Wheel. When more than one number wheel are employed, they are usually interrelated by Geneva elements whereby at the end of a revolution of the first number wheel, a second number wheel is rotated one step, and so on. In certain types of counters which can'be reset to zero, the transmission between driver gear and Wheel must be such that a slip-clutch action permits overriding rotation of the wheel without disconnecting the drive connection to the driver gear.

Number wheels are disclosed in the prior art but so far as applicant is aware they have been mechanical assemblies tedious and expensive to put together, somewhat excessive in weight, and lacking permanent simplified unification.

SUMMARY OF THE INVENTION The number wheel of the present invention is compact, lightweight, conveniently fabricated, and embodies a unique permanent sandwich-type assembly of wheel, driver gear and ratchet-type slip clutch. v

The objective is accomplished by forming a wheel in generally cup shape of a material, preferably a plastic which is susceptible to welding by ultrasonic vibration. The wheel includes a hub from an end face of which one or more facets project, the hub including the facets being of the same material and integral with the wheel. A spring detent member is positioned against a web of the hub, being located by apertures through which the facets extend.

A secondary hub member made of the same material as the wheel, or any suitable material which can be ultrasonically welded thereto is utilized to rotatably mount the driver gear.

The driver gear is made of lightweight material, preferably a plastic, but of a character which Will not weld to the hubs. It is retained on the secondary hub by a thrust flange integral with the hub.

The secondary hub, carrying the driver gear, is permanently attached to the primary hub. It is conveniently centered thereon by fitting over a stub extension of the primary hub. The preferred method of attachment is to subject the assembled parts to pressure and vibration by an ultrasonic generator, which will weld the two hubs into a unitary homogeneous and integral component.

The ratchet-type slip clutch comprises a surface on the driver gear formed with radially extending ratchet teeth, cooperatively engaging with the spring detent. The resilient engagement is adequate for the driver gear to turn the lightweight wheel, but Will yield when the driver gear is restrained and the wheel is forcibly rotated for resetting the latter.

A spring biased pawl is nested in a recess in the composite hub assembly, being held between adjacent surfaces of the primary hub and the spring detent member. The pawl rides freely in and out of a notch in a reset shaft when the driver gear is allowed to advance the Wheel, but drops into the notch and is retained there when the shaft is rotated in the resetting direction.

The driver gear may be rotated by any mechanical means such as gearing, ratcheting, etc. The wheel may have appended thereto a Geneva tooth for transfer of rotation in predetermined increments from one number wheel to an adjacent one.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a front elevation of a number wheel made in accordance with the invention.

FIGURE 2 is a similar view, enlarged and partly in section.

FIGURE 3 is a vertical sectional view taken on the line 3-3 of FIGURE 2.

FIGURE 4 is a vertical sectional view taken on the line 4-4 of FIGURE 2.

FIGURE 5 is a fragmentary side view of a Geneva tooth transfer on the wheel.

FIGURE 6 is a perspective of the pawl reset member.

FIGURE 7 is a perspective of the spring which biases the pawl.

FIGURE 8 is an exploded view pertly in section of the parts which make up the number wheel, with a pressure plate and an ultrasonic generator indicated schematically.

FIGURE 9 is a vertical sectional view of the parts of FIGURE 8 as permanently assembled.

FIGURE 10 is an enlarged fragmentary view showing parts assembled before welding.

FIGURE 11 is a similar view after welding is completed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The wheel 20 is generally cup shaped. The wall of the cup is in the form of a plane cylindrical wheel rim 21 on which any desired numbers 22 may appear, as for example 0 through 9, or more. The rim is made relatively thin compared to the wheel hub 23, which latter is mountable on a reset shaft 24. The inner end of the hub is enlarged into an annular web 25, and a frusto conical wheel disk 26 extends from the web into conjunction with the rim.

The Wheel initially is provided on the end surface of the annular web 25 with a plurality of facets 30 which are used as locators for a spring detent member 31 and as Welding attachments for a secondary hub 32.

The annular web 25 is also formed with an elongated recess 33 which has open communication with the interior of the wheel hub. This recess is specially formed with enlarged circular ends 33' and 33". A pawl 34 and a generally hairpin shaped spring 35 are oppositely mounted in the recess, with the spring biasing the shank of the pawl against the shaft. Pawl and spring are each shaped with an enlarged end which fits into the ends 33' and 33 respectively of the recess for maintaining the pawl and spring captive in the recess. The shaft has a notch 36 in vertical alignment with the pawl. When the Wheel is rotated in a direction to advance the numbers (FIG- URE 3), the pawl rides over the shaft. When the shaft is rotated to reset the wheel, the pawl becomes engaged in the notch to transmit the rotation to reset the wheel (FIGURE 4). The pawl and spring may be reversed in position, whereby the wheel is rendered bidirectional.

A generally annular stub extension 37 extends inward- 1y from the web 25 as a continuation of the hub 23. It is interrupted at 38 where the recess 33 communicates with the interior of the hub. At its outer end a bore 39 is formed to accommodate a ring 40 which axially positions the wheel on the shaft. Thus, in the event of high temperature or humidity, a set of wheels will not have a thermoexpansion which will cause them to contact one another. Misalignment of spur gears is also thereby prevented.

The detent member 31 is in the form of a thin disk 41 with spring characteristics. It has a central aperture 42 which fits over the extension 37, and it also has a plurality of smaller apertures 43 which can register with the Welding facets 30. These facets extend through the apertures 43, and the latter preferably are of a diameter slightly greater than that of the facets for reception of fiowable material when welding takes place.

On the inner face of the disk 41 one or more detents (teeth) 48 may be provided. Conveniently, they may be struck from the material of the disk itself, and preferably there are two of them diametrically spaced to give proper balance.

Contiguous to the disk is positioned the secondary hub 32. It has a socket 49 which is engageable with the extension 37 to axially relate the parts. It is welded to the annular web 25 through the agency of the facets 30 in a manner to be later described. The secondary hub embodies a rim 50 terminating in a flange 51. The rim 50 provides an axle type bearing for a driver gear 52, and the flange 51 functions as a thrust retainer of the gear, confining the latter between the disk 41 and the flange 51, the gear 52 being rotatable on the rim 50.

The gear 52 includes a relatively large diameter section '53 with peripheral teeth 54 which can be engaged by any suitable driver, as for example by a spur gear 55 taking rotation from a source to be measured.

The driver gear also includes an annular axial offset 56 of relatively smaller outside diameter (corresponding generally to the outside diameter of the detent disk 41). The face of the annular offset is formed with radially extending ratchet teeth 58 for engagement by the detents 48.

When the gear 52 is driven, rotation is imparted to the detent disk through the ratchet teeth 58 resiliently engaged by the detents 48. By the rigid securement of the detent disk to the annular web 25 the wheel is rotated in a counting direction.

The wheel may be provided with Geneva teeth 60 engageable by any suitable Geneva element 61 for transferring rotation of the wheel to another wheel in series.

For resetting the wheel, the shaft 24 is manually rotated so as to bring the notch 36 into engagement with the pawl 34, and the latter transmits rotation to the hub assembly. The gear section 53 is restrained by the spur gear during reset. However, the resiliency of the detent member 31 permits the detents to ride over the ratchet teeth 58, and the wheel may be turned to zero or to any number desired.

The method of fabricating the wheel is an important phase of the invention. It avoids the use of screws, clamps, adhesives, and any other conventional assembly devices, which are cumbersome and difficult to employ, especially in miniature size number Wheels. Furthermore, it results in a unified assembly which will remain intact under all ordinary service conditions.

The wheel and the secondary hub are formed of ultrasonically weldable plastic, one example of which is nylon.

The detent spring disk and its teeth may be satisfactorily formed of any spring material.

The driver gear should not be ultrasonically weldable under the same conditions that the wheel and hub are weldable. A good material for that purpose is a tough plastic available as Du Pont Delrin Acetal.

These named materials are by way of illustration and not of limitation.

In completing the assembly a fixture should be held on one side, as illustrated in FIGURE 8, and an ultrasonic vibration should be applied to the other side. A suitable ultrasonic generator, which is known, produces vibrations at a frequency suitable to generate heat between the two surfaces so as to weld them. The vibrations are transmitted to the weldable parts through a horn or rod shaped structure, as schematically shown in FIG- URE 8.

The latter figure in the drawings illustrates the method referred to. It comprises the several steps of forming the wheel of an ultrasonically weldable plastic with a primary hub having an end surface 62 and including a facet of the same material integral with the hub and extending outwardly of the surface parallel to the hub axis, forming a secondary hub of the same material or material adaptable to the same type of welding, and with an annular bearing surface for a driver gear, and with an end surface 63 suitable for mating with the end surface of the primary' hub. A spring detent member is formed with an aperture therein which will allow the facet to extend through. The detent member is placed against the end surface of the primary hub with the facet extending through the aperture. A driver gear is prepared of a material not receptive to ultrasonic welding and this is placed on the bearing surface of the secondary hub. A pawl and spring are disposed in a recess in the primary hub. The assembly of the gear and secondary hub is then placed in axial alignment with the primary hub with its end surface facing the end surface of the primary hub. The assembly is placed in a holding fixture. This is preferably performed by disposing the block horizontal from the position shown in FIGURE 8) and stacking the parts thereon. A vibratory condition is then imparted to the hubs by an ultrasonic generator to weld the facet to the end surface of the primary hub, and thus forming a joint between the hubs resulting in a unitary hu'b assembly with the detent between the hub in a permanent structure. It is preferable also in forming the secondary hub to provide a flange to retain the driver gear on the secondary hub.

The vibration imparted by the ultrasonic generator affects only the contiguous material of the primary and sec ondary hubs. It appears that the facets of the primary hub become heated and flowable and not only fill the space in the aperture of the detent disk but flatten out and weldably merge with the contacting surface of the secondary hub, as seen in FIGURE 11, so that when the welding is completed not only is the detent disk securely held in place but the primary and secondary hubs are completely unitary and for all practical purposes are homogeneous and integral. Furthermore, the pawl and spring are movably trapped in their recess, and the driver gear is captive for rotation on the rim of the secondary hub.

The wheel (primary) hub, the detent member, and the secondary hub are fixed rigidly together by the welding, so that there is no axial or radial play between these parts.

The counter wheel of the present invention may be either the units wheel, the tens wheel, or any other wheel. Further, the units wheel may be driven in step-fashion or it may be driven continuously.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and methods.

What is claimed is:

1. A method of fabricating a number wheel which includes the following steps: forming a wheel member of an ultrasonically weldable plastic with a primary hub having an end surface, providing an integral facet of the same material extending outwardly from said surface parallel to the hub axis, forming a secondary hub of similar material with an annular bearing surface for a driver gear and with an end surface suitable for mating with the facet on the end surface of the primary hub, forming a spring detent member and providing an aperture therein which will allow the facet to extend through, placing the detent member against the end surface of the primary hub with the facet extending through the aperture, placing the secondary hub in axial alignment with the primary hub with its end surface facing toward the end surface of the primary hub, then applying vibration to the hubs by an ultrasonic generator to weld the facet to the end surface of the secondary hub and thus form a unitary hu-b assembly with the detent between the hubs in a permanent sandwich-type structure.

2. A method as defined in claim 1 which includes the additional steps of forming a gear retention flange on the secondary hub, forming a driver gear with peripheral gear teeth and an annular ratchet surface suitable for engagement with the detent member and of a material which will not be welded to the hubs, under the same welding conditions and placing the gear on the bearing surface of the secondary hub before performing the Welding step so that when the welding is completed the gear is rotatably and permanently assembled with the hub assembly.

3. A method as defined in claim 2 wherein plastic material adaptable to ultrasonic welding is used for both hubs including the facet, a spring material is used for the detent member, and a different plastic material which is not adaptable to ultrasonic welding under the same conditions is used for the driver gear.

4. A method as defined in claim 1 which includes the additional steps of forming a recess in the end face of the primary hub, and placing a pawl and spring in the recess for yieldable engagement with a reset shaft before placing the detent member against said end surface.

5. A method as defined in claim 1 which includes the additional step of providing an axial aligning means between the hubs by suitable fixturing before applying the welding vibration to the hubs.

'6. The method of fabricating a laminate-like structure,

said method comprising the steps of: placing a projection fixed to one outer layer through a hole in an intermediate layer; placing another outer layer in contact with the end of said projection; and vibrating both of said outer layers together to generate heat sufficient to weld said projection to said other outer layers.

7. The invention as defined in claim 6, wherein the volume of said projection is displaced during welding so that said displaced volume at least partially fills the clearance space inside said intermediate layer hole taking up the fit tolerance.

8. The invention as defined in claim 7, wherein said displaced volume completely fills said clearance space.

9. The invention as defined in claim 8, wherein said one outer layer has another projection placed through a second hole in said intermediate layer and similarly welded to said outer layer.

References Cited Using Ultrasonics to Assemble Plastic Parts, Edward Obeda, Automation, November 1967, pp. 78-82.

BEN R. PADGETI, Primary Examiner A. J. STEINER, Assistant Examiner U.S. Cl. X.R. 156-293 

